1. Field of the Invention
The invention relates to hook driving mechanism for sewing machines having a vertical axis hook.
2. Description of the Prior Art
In sewing machines having a vertical axis hook, it is common practice to drive the hook through a pair of meshing bevel gears, the input gear of which is rotated about a horizontal axis by an input bed shaft and the other gear of which is driven by the input gear about a vertical axis. Heretofor the input gear has been affixed to the bed shaft, as for example, by a set screw, and because of dimensional tolerances associated with the outer diameter of the shaft and inside diameter of the input gear, such gear was forced into an eccentric position relative to the shaft axis. As a consequence, the meshing gears did not properly engage through 360.degree. of rotation and excessive noise resulted. In constructions wherein the vertical axis gear, hereinafter referred to as the hook driving gear, was secured to a hook shaft by a set screw and thereby caused to assume an eccentric position relative to axis of such hook shaft, the problem was further aggrevated.
It is a prime object of this invention to provide a sewing machine with an improved hook drive train wherein meshing gears operate smoothly without accompanying noise.